aboutsummaryrefslogtreecommitdiff
path: root/src/WifiAP.cpp
blob: 3a5de3705ce11cde5d05a2e5f39757e0b1ec6b68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
/*
    Copyright 2016-2020 Arisotura

    This file is part of melonDS.

    melonDS is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with melonDS. If not, see http://www.gnu.org/licenses/.
*/

#include <stdio.h>
#include <string.h>
#include "NDS.h"
#include "Wifi.h"
#include "WifiAP.h"
#include "Platform.h"

#ifndef __WIN32__
#include <stddef.h>
#endif

namespace WifiAP
{

#define AP_MAC  0x00, 0xF0, 0x77, 0x77, 0x77, 0x77
#define AP_NAME "melonAP"

const u8 APMac[6] = {AP_MAC};

#define PWRITE_8(p, v)      *p++ = v;
#define PWRITE_16(p, v)     *(u16*)p = v; p += 2;
#define PWRITE_32(p, v)     *(u32*)p = v; p += 4;
#define PWRITE_64(p, v)     *(u64*)p = v; p += 8;

#define PWRITE_MAC(p, a,b,c,d,e,f) \
    *p++ = a; *p++ = b; *p++ = c; *p++ = d; *p++ = e; *p++ = f;

#define PWRITE_MAC2(p, m) \
    *p++ = m[0]; *p++ = m[1]; *p++ = m[2]; *p++ = m[3]; *p++ = m[4]; *p++ = m[5];

#define PWRITE_SEQNO(p)     PWRITE_16(p, SeqNo); SeqNo += 0x10;

#define PWRITE_TXH(p, len, rate) \
    PWRITE_16(p, 0); \
    PWRITE_16(p, 0); \
    PWRITE_16(p, 0); \
    PWRITE_16(p, 0); \
    PWRITE_8(p, rate); \
    PWRITE_8(p, 0); \
    PWRITE_16(p, len);

//#define PALIGN_4(p, base)  p += ((4 - ((ptrdiff_t)(p-base) & 0x3)) & 0x3);
// no idea what is the ideal padding there
// but in the case of management frames the padding shouldn't be counted as an information element
// (theory: the hardware just doesn't touch the space between the frame and the FCS)
#define PLEN(p, base)      (int)(ptrdiff_t)(p-base)
#define PALIGN_4(p, base)  while (PLEN(p,base) & 0x3) *p++ = 0xFF;


u64 USCounter;

u16 SeqNo;

bool BeaconDue;

u8 PacketBuffer[2048];
int PacketLen;
int RXNum;

u8 LANBuffer[2048];

// this is a lazy AP, we only keep track of one client
// 0=disconnected 1=authenticated 2=associated
int ClientStatus;


bool Init()
{
    return true;
}

void DeInit()
{
}

void Reset()
{
    // random starting point for the counter
    USCounter = 0x428888017ULL;
    SeqNo = 0x0120;

    BeaconDue = false;

    memset(PacketBuffer, 0, sizeof(PacketBuffer));
    PacketLen = 0;
    RXNum = 0;

    ClientStatus = 0;
}


bool MACEqual(u8* a, u8* b)
{
    return (*(u32*)&a[0] == *(u32*)&b[0]) && (*(u16*)&a[4] == *(u16*)&b[4]);
}

bool MACIsBroadcast(u8* a)
{
    return (*(u32*)&a[0] == 0xFFFFFFFF) && (*(u16*)&a[4] == 0xFFFF);
}


void USTimer()
{
    USCounter++;

    u32 chk = (u32)USCounter;
    if (!(chk & 0x1FFFF))
    {
        // send beacon every 128ms
        BeaconDue = true;
    }
}


int HandleManagementFrame(u8* data, int len)
{
    // TODO: perfect this
    // noting that frames sent pre-auth/assoc don't have a proper BSSID
    //if (!MACEqual(&data[16], (u8*)APMac)) // check BSSID
    //    return 0;

    if (RXNum)
    {
        printf("wifiAP: can't reply!!\n");
        return 0;
    }

    u16 framectl = *(u16*)&data[0];

    u8* base = &PacketBuffer[0];
    u8* p = base;

    switch ((framectl >> 4) & 0xF)
    {
    case 0x0: // assoc request
        {
            if (!MACEqual(&data[16], (u8*)APMac)) // check BSSID
                return 0;

            if (ClientStatus != 1)
            {
                printf("wifiAP: bad assoc request, needs auth prior\n");
                return 0;
            }

            ClientStatus = 2;
            printf("wifiAP: client associated\n");

            PWRITE_16(p, 0x0010);
            PWRITE_16(p, 0x0000); // duration??
            PWRITE_MAC2(p, (&data[10])); // recv
            PWRITE_MAC2(p, APMac); // sender
            PWRITE_MAC2(p, APMac); // BSSID
            PWRITE_SEQNO(p);

            PWRITE_16(p, 0x0021); // capability
            PWRITE_16(p, 0); // status (success)
            PWRITE_16(p, 0xC001); // assoc ID
            PWRITE_8(p, 0x01); PWRITE_8(p, 0x02); PWRITE_8(p, 0x82); PWRITE_8(p, 0x84); // rates

            PacketLen = PLEN(p, base);
            RXNum = 1;
        }
        return len;

    case 0x4: // probe request
        {
            // Nintendo's WFC setup util sends probe requests when searching for APs
            // these should be replied with a probe response, which is almost like a beacon

            PWRITE_16(p, 0x0050);
            PWRITE_16(p, 0x0000); // duration??
            PWRITE_MAC2(p, (&data[10])); // recv
            PWRITE_MAC2(p, APMac); // sender
            PWRITE_MAC2(p, APMac); // BSSID (checkme)
            PWRITE_SEQNO(p);

            PWRITE_64(p, USCounter);
            PWRITE_16(p, 128); // beacon interval
            PWRITE_16(p, 0x0021); // capability
            PWRITE_8(p, 0x01); PWRITE_8(p, 0x02); PWRITE_8(p, 0x82); PWRITE_8(p, 0x84); // rates
            PWRITE_8(p, 0x03); PWRITE_8(p, 0x01); PWRITE_8(p, 0x06); // current channel
            PWRITE_8(p, 0x00); PWRITE_8(p, strlen(AP_NAME));
            memcpy(p, AP_NAME, strlen(AP_NAME)); p += strlen(AP_NAME);

            PacketLen = PLEN(p, base);
            RXNum = 1;
        }
        return len;

    case 0xA: // deassoc
        {
            if (!MACEqual(&data[16], (u8*)APMac)) // check BSSID
                return 0;

            ClientStatus = 1;
            printf("wifiAP: client deassociated\n");

            PWRITE_16(p, 0x00A0);
            PWRITE_16(p, 0x0000); // duration??
            PWRITE_MAC2(p, (&data[10])); // recv
            PWRITE_MAC2(p, APMac); // sender
            PWRITE_MAC2(p, APMac); // BSSID
            PWRITE_SEQNO(p);

            PWRITE_16(p, 3); // reason code

            PacketLen = PLEN(p, base);
            RXNum = 1;
        }
        return len;

    case 0xB: // auth
        {
            if (!MACEqual(&data[16], (u8*)APMac)) // check BSSID
                return 0;

            ClientStatus = 1;
            printf("wifiAP: client authenticated\n");

            PWRITE_16(p, 0x00B0);
            PWRITE_16(p, 0x0000); // duration??
            PWRITE_MAC2(p, (&data[10])); // recv
            PWRITE_MAC2(p, APMac); // sender
            PWRITE_MAC2(p, APMac); // BSSID
            PWRITE_SEQNO(p);

            PWRITE_16(p, 0); // auth algorithm (open)
            PWRITE_16(p, 2); // auth sequence
            PWRITE_16(p, 0); // status code (success)

            PacketLen = PLEN(p, base);
            RXNum = 1;
        }
        return len;

    case 0xC: // deauth
        {
            if (!MACEqual(&data[16], (u8*)APMac)) // check BSSID
                return 0;

            ClientStatus = 0;
            printf("wifiAP: client deauthenticated\n");

            PWRITE_16(p, 0x00C0);
            PWRITE_16(p, 0x0000); // duration??
            PWRITE_MAC2(p, (&data[10])); // recv
            PWRITE_MAC2(p, APMac); // sender
            PWRITE_MAC2(p, APMac); // BSSID
            PWRITE_SEQNO(p);

            PWRITE_16(p, 3); // reason code

            PacketLen = PLEN(p, base);
            RXNum = 1;
        }
        return len;

    default:
        printf("wifiAP: unknown management frame type %X\n", (framectl>>4)&0xF);
        return 0;
    }
}


int SendPacket(u8* data, int len)
{
    data += 12;

    u16 framectl = *(u16*)&data[0];
    switch ((framectl >> 2) & 0x3)
    {
    case 0: // management
        return HandleManagementFrame(data, len);

    case 1: // control
        // TODO ???
        return 0;

    case 2: // data
        {
            if ((framectl & 0x0300) != 0x0100)
            {
                printf("wifiAP: got data frame with bad fromDS/toDS bits %04X\n", framectl);
                return 0;
            }

            // TODO: WFC patch??

            if (*(u32*)&data[24] == 0x0003AAAA && *(u16*)&data[28] == 0x0000)
            {
                if (ClientStatus != 2)
                {
                    printf("wifiAP: trying to send shit without being associated\n");
                    return 0;
                }

                int lan_len = (len - 30 - 4) + 14;

                memcpy(&LANBuffer[0], &data[16], 6); // destination MAC
                memcpy(&LANBuffer[6], &data[10], 6); // source MAC
                *(u16*)&LANBuffer[12] = *(u16*)&data[30]; // type
                memcpy(&LANBuffer[14], &data[32], lan_len - 14);

                Platform::LAN_SendPacket(LANBuffer, lan_len);
            }
        }
        return len;
    }

    return 0;
}

int RecvPacket(u8* data)
{
    if (BeaconDue)
    {
        BeaconDue = false;

        // craft beacon
        u8* base = data + 12;
        u8* p = base;

        PWRITE_16(p, 0x0080);
        PWRITE_16(p, 0x0000); // duration??
        PWRITE_MAC(p, 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF); // recv
        PWRITE_MAC2(p, APMac); // sender
        PWRITE_MAC2(p, APMac); // BSSID
        PWRITE_SEQNO(p);

        PWRITE_64(p, USCounter);
        PWRITE_16(p, 128); // beacon interval
        PWRITE_16(p, 0x0021); // capability
        PWRITE_8(p, 0x01); PWRITE_8(p, 0x02); PWRITE_8(p, 0x82); PWRITE_8(p, 0x84); // rates
        PWRITE_8(p, 0x03); PWRITE_8(p, 0x01); PWRITE_8(p, 0x06); // current channel
        PWRITE_8(p, 0x05); PWRITE_8(p, 0x04); PWRITE_8(p, 0); PWRITE_8(p, 0); PWRITE_8(p, 0); PWRITE_8(p, 0); // TIM
        PWRITE_8(p, 0x00); PWRITE_8(p, strlen(AP_NAME));
        memcpy(p, AP_NAME, strlen(AP_NAME)); p += strlen(AP_NAME);

        PALIGN_4(p, base);
        PWRITE_32(p, 0xDEADBEEF); // checksum. doesn't matter for now

        int len = PLEN(p, base);
        p = data;
        PWRITE_TXH(p, len, 20);

        return len+12;
    }

    if (RXNum)
    {
        RXNum = 0;

        u8* base = data + 12;
        u8* p = base;

        memcpy(p, PacketBuffer, PacketLen);
        p += PacketLen;

        PALIGN_4(p, base);
        PWRITE_32(p, 0xDEADBEEF);

        int len = PLEN(p, base);
        p = data;
        PWRITE_TXH(p, len, 20);

        return len+12;
    }

    if (ClientStatus < 2) return 0;

    int rxlen = Platform::LAN_RecvPacket(LANBuffer);
    if (rxlen > 0)
    {
        // check destination MAC
        if (!MACIsBroadcast(&LANBuffer[0]))
        {
            if (!MACEqual(&LANBuffer[0], Wifi::GetMAC()))
                return 0;
        }

        // packet is good

        u8* base = data + 12;
        u8* p = base;

        PWRITE_16(p, 0x0208);
        PWRITE_16(p, 0x0000); // duration??
        PWRITE_MAC2(p, (&LANBuffer[0])); // recv
        PWRITE_MAC2(p, APMac); // BSSID
        PWRITE_MAC2(p, (&LANBuffer[6])); // sender
        PWRITE_SEQNO(p);

        PWRITE_32(p, 0x0003AAAA);
        PWRITE_16(p, 0x0000);
        PWRITE_16(p, *(u16*)&LANBuffer[12]);
        memcpy(p, &LANBuffer[14], rxlen-14); p += rxlen-14;

        PALIGN_4(p, base);
        PWRITE_32(p, 0xDEADBEEF); // checksum. doesn't matter for now

        int len = PLEN(p, base);
        p = data;
        PWRITE_TXH(p, len, 20);

        return len+12;
    }

    return 0;
}

}